This invention relates generally to a flight control system. More specifically the invention pertains to helicopter rotor head control means which provide fail-safe functioning of this operational component.
The usual control of the helicopter during its operation is achieved by the provision of a swashplate. The swashplate is tilted about a tilting axis transverse to the rotor shaft to regulate the pitch and functioning of the helicopter blade assembly. Mechanical or servo controls connected by mechanical linkages cause the swashplate to tilt in phase with the cycle of rotation. Such controls have operated reasonably effectively in maintaining precision control over the pitch of the swashplate, thereby regulating the rotary head that supports the various blades of the helicopter blade assembly. However the mechanical linkages are normally so constructed that a failure of any one of the servo mechanisms operatively associated with a linkage (or with a control valve) can result in a loss of control of the helicopter during flight. Thus, particularly during combat conditions, when mechanical controls have been operationally impaired, either by a direct hit, or a curtailing of functioning due to a nearby impacting explosion, substantial loss of life and aircraft has been sustained.
This invention is designed to rectify the problem of loss of swashplate control by the provision of back up control means. An object of this invention is the provision of a control system for maintaining the operation of a flight control system for a helicopter in fail-safe operation under the most adverse of conditions.
Another object of this invention is to provide not only the usual servo mechanical valve means for moving the swashplate actuators, but to provide secondary swashplate actuators responding to the control means built into the flight control system of this invention.
These and other objects will become more apparent to those skilled in the art upon reviewing the summary of this invention, and upon undertaking a study of its preferred embodiment in view of its drawing.